18520915220 has 18 divisors (see below), whose sum is σ = 38895200106. Its totient is φ = 7408122640.

The previous prime is 18520915201. The next prime is 18520915229. The reversal of 18520915220 is 2251902581.

It can be written as a sum of positive squares in only one way, i.e., 14816732176 + 3704183044 = 121724^2 + 60862^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18520915229) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 593405 + ... + 623835.

Almost surely, 2^18520915220 is an apocalyptic number.

18520915220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18520915220 is an abundant number, since it is smaller than the sum of its proper divisors (20374284886).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18520915220 is an frugal number, since it uses more digits than its factorization.

18520915220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60871 (or 30438 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 35.

The spelling of 18520915220 in words is "eighteen billion, five hundred twenty million, nine hundred fifteen thousand, two hundred twenty".